I'm a co-founder of NorthBridge Energy Partners, LLC., a consulting firm that helps companies connect assets to power grids. I'm also a former Senior VP of Energy Technology Services for Constellation NewEnergy, Inc., and have 20+ years of experience in the energy industry. I've written for the Boston Business Journal, Mass High Tech and several other online industry publications. I have a B.A. from Williams College and a Masters from Tufts University’s Fletcher School.

Although the initial numbers are small, the trend is worth watching, as some of the pieces of the electric car puzzle are finally fitting together. Nissan just announced that it will ramp up U.S. assembly of the 2013 model year all-electric LEAF at its manufacturing plant in Smyrna, Tenn. The Leaf will be made in the same plant, on the current Altima and Maxima line, and next to Nissan’s gasoline-powered vehicles, and next door to the largest lithium-ion automotive battery plant in the U.S. The goal is to lower costs and appeal to a broader spectrum of customers. In all of 2012, Nissan sold 9,819 Leafs with about 19,500 on the road in the US, and 50,000 worldwide. And of course, Toyota has come out with its Plug-in hybrid Prius, selling 12,750 units in the last last year alone. In fact the total plug-in sales tripled from just over 17,500 in 2011 to about 53,000 in 2012.

Meanwhile, other entrants from the major car companies – from BMW to Mitsubishi – are joining the market. And there are the pure plays as well, such as Fisker and Tesla. The latter’s Model S – at $58,570 and priced competitively among relevant high-performance peers – just won 2013 Motor Trend Car of the Year, with the magazine commenting “The 2013 Motor Trend Car of the Year is one of the quickest American four doors ever built. It drives like a sports car, eager and agile and instantly responsive. But it’s also as smoothly effortless as a Rolls-Royce, can carry almost as much stuff as a Chevy Equinox, and is more efficient than a Toyota Prius…By any measure, the Tesla Model S is a truly remarkable automobile, perhaps the most accomplished all new luxury car since the original Lexus LS 400…At its core, the Tesla Model S is simply a damned good car you happen to plug in to refuel.” (It’s that kind of comment that suggest that alternative technologies in transportation have truly arrived. They are no longer green curiosities – they are great vehicles).

Tesla not only makes a great car, but it seems to have turned the corner on production volumes as well. In Q3 of last year, they went from making 5 cars per week to 100. By November, they had scaled to 200 cars per week, and have a goal of 20,000 for 2013.

So the era of the electric car appears to be dawning upon us. But what about the charging side of the equation? What does that mean for our electric power grid? The first thing to understand is that electric vehicle adoption has been hampered by a fear of running out of electricity, so-called ‘range anxiety,’ since they don’t get the hundreds of miles per fill-up one gets with a gasoline-powered vehicle. The lithium ion batteries simply do not yet have that capacity. To account for this, networks of charging stations are being built across North America. There are standards emerging for these chargers, but there is still some confusion among options.

For its part, the electric energy utility NRG, is taking a dramatic and aggressive approach to move into this space. Through eVgo they offer network charging, where users have the option to pay a fixed monthly fee of as little as $19/month to charge up at DC Fast Charger sites, getting 50 miles of range in 15 minutes, ands they also provide an option for a slow charge as well. They also offer a program to plug in for extended times (at work places or multi-family sites) of 4-8 hours. Finally, eVgo will set up a home charging station for the individual user, with plans at $59/month. Their network started in the Houston and Dallas locations, but they are now extending into California and the Northeast. In California alone (as part of a settlement with the State over issues occurring suring the CA energy crisis over a decade ago) NRG has agreed to build and operate infrastructure for at least 200 fast-charging (480 volt) stations, and a minimum 10,000 level 2 (240 volt) stations in businesses and multi-unit dwellings.

The home charging infrastructure is also getting cheaper and more easily accessible. Lowes, Best Buy, and others now offer charging stations from manufacturers such as Schneider, Leviton, and GE in the $750-1000 cost range.

There are currently over 15,000 charging stations across the U.S., with many of them 240 volt rapid chargers. With that kind of draw on electricity demand, the obvious question is what will happen to peak demand. Will EV drivers draw so much power during driving hours (rush hour, or mid-day), that it contributes to overall peak demand? If so, this would be precisely the opposite of the reason the utilities originally hailed electric cars. The thought ten years ago was that they would mostly be charged at night, filling in the valley of low off-peak demand, and thus allowing more kilowatt-hours to flow across the same infrastructure. However, with rapid charging at higher voltages and kW levels, the dynamic could potentially push exactly the other way.

Let’s look at the actual charging capacities to get a sense of the potential magnitude: In the extreme, Tesla is offering a super high voltage charging opportunity, providing a range of 150 miles to its Model S 85 kilowatt-hour (kWh) battery in about 30 minutes. The charge capability is 480 volt, with a maximum 90 kilowatt (kW) draw. That level of voltage and capacity is quite significant. To put it in perspective, for planning purposes the California Energy Commission assumes the average residential household to have a peak ranging between 1.8 and 2.4 kW. So the supercharge station with 90 KW essentially packs the punch of about 40 households worth of peak demand. Looked at another way, a Sears/Kmart store might have 300 kW of peak demand, just over 3x what a single car battery charge would draw for a short period.

The other charging stations out there don’t pack quite the same firepower, but the standard level 2 240-volt chargers can draw up to 19 kW during periods lasting from 30 minutes to 3 hours. With increasing numbers of these stations, what is the potential impact to the electric grid?

Deloitte looked at precisely this issue recently, in its report Charging Ahead: The Last Mile. They interviewed numerous utility planners summarized “Surprisingly, we found that in general, the electric utility infrastructure is already prepared to meet the President’s 2015 challenge. Our research revealed that utilities will not likely need to upgrade or expand transmission or generation capacity in the next ten years specifically to meet electric demand from EVs at projected adoption rates….However, the research did identify near-term impacts to the electric infrastructure that deserve further study at the local distribution level, ‘the last mile,’ including possible clustering of EVs on low-capacity distribution transformers, such as 25 kVA , and the potential impact on local transformers of any capacity if clusters of EVs charge simultaneously during hours of peak electric demand. The research also showed that utilities are studying and addressing these impacts”.

The major findings:

1) Almost all the utilities surveyed had studied the impacts of EVs on their supply infrastructure, with the most common focus being on distribution level impacts, home charging stations, peak-hour charging, and research into transformers.

2) Nearly three-quarters of the utilities do not foresee an impact on the need for new generating capacity, and two-thirds feel they have adequate transmission infrastructure in place. Just over a tenth raised concerns about transformer overloading.

3) However, fully half indicated they are not notified when a ratepayer purchases an electric vehicle in their service territory (a few areas, such as California are working to design notification processes, and the Texas utilities have proposed a law requiring such notification).

For now, at least, any infrastructure problems appear to be at the local level. The concern of some in that area has to do with – ironically – peak demand at night. If a number of 240 volt chargers – which could recharge a car in 2-3 hours – were to be deployed in the evening, during off-peak rates designed to take peak demand from the grid, one might burn out the street-level transformers. “Many of these are undersized and designed to cool at night. Without time to cool, sustained excess current will eventually cook a transformer’s copper windings, causing a short and blacking out the local loads it serves,” according to an article in the IEEE.

This problem may be more than just theoretical. Data concerning the habits of EV owners in an Austin, TX suburb, indicated that over a two month period the residents generally tended to recharge at the same time – when returning from work. This also happened to be when many residents were also turning on air conditioning and other appliances.

At this point, it’s pretty evident that electric cars are coming into vogue and that at least in the short-term, we probably won’t have major difficulties absorbing them into the system. It’s also clear that they may have profound implications for the power grid in the longer-term, based on behavioral issues, tariff policies, emerging technology, and economics. This trend bears watching, and the utilities should be paying close attention to both volumes sold and user behavior. As electric and transportation systems collide, unexpected outcomes should not surprise us.

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I’m curious if the author is aware that Better Place have deployed and are operating a smart car charging grid in Denmark and Israel that both have the capacity to delay the start of evening charging according to the wishes of the power generating companies in those countries? I’m a customer in Israel.

I’m not sure they’ve had to do this yet (subscriber numbers not significant enough) but I do know that just plugging in my car does not guarantee that current will flow immediately. I can request immediate charge but if I don’t need the car for 10 hours, I wouldn’t do that and so it would be fine for charging to be delayed till later in the evening.

I’m aware of the Better Place model and have been following for years. I love the concept of the swappable battery. I don’t know how you reach ubiquity to get to scale. Its like Sony vs Betamax vs Concept A vs Concept B vs Concept C with a multitude of formats. Even the charging format for the non-Better Place models is not entirely resolved. To your latter point, we are so conditioned to getting energy when and where we want it, I’m not sure we will have patience for trickle charging. Plus, batteries will get bigger for extended range – which means more juice…

It’s not really about patience for trickle, it’s about delayed gratification. I arrived home with about 60% battery today at 6pm I know I’m not going to use the car till 8am tomorrow. I really don’t care when it fills up. Now if I knew I had to go out at 8pm I do have a button to request priority charge. Up to now every connection is immediate so this is redundant but last summer were were in serious trouble in Israel with our supply of peak electricity.

The switching always grabs the headlines for Better Place but the managed grid is much more important and the range prediction system we have (Tesla haven’t got this) is very effective. I’ve read mountains of stuff about smart grids but haven’t heard one single suggestion that makes sense other than delaying car charging. There is almost nothing else of any significant size that domestic supply can defer without inconveniencing the user.

Fast charging, however, is a big disaster: users want it, and they want it NOW. Even within a battery switch station, where multiple batteries can be in varying states of fast recharge, Better Place can slow or temporarily cut charging if the grid has a problem. This isn’t possible for fast charging networks for cars.

I do like the idea of managed and centralized thinking applied to the problem. I’m just not sure how Better Place will win with its model. I think it’s elegant and I used to think “wouldn’t it be cool if you could just swap out a ‘cartridge’?” I certainly BP luck.

One thing you didn’t mention about the supercharger stations that Tesla is building, is that they are solar-powered. Hopefully, this will relieve the power grid of some peak charging issues that this article is concerned with. But for us folks charging at home at night, it is typical to come home from work and attach it to the charger…and that is still peak daytime. So, I will likely change what time I actually begin my charging going forward!

Susan – thanks for the comment. I like the fact that they are solar powered, but it will take a heck of a lot of real estate to generate enough kWh to reach 100% of the energy used. 85 kWh is not insubstantial.

As far as home charging stations, they will be OK for many hybrid gas-electrics, less so for all-electrics that need 200+ miles of range. Thanks again for the dialogue.

Of the eight supercharger locations announced thus far, only the one at Harris Ranch has a solar array over the recharging spots; it’s capable of producing enough energy to recharge 2 or 3 85kwh packs/week.

There are only two supercharger locations along the east coast, both grid fed. Not so much sunshine at those latitudes, but those details get in the way of the story being spun.

Excellent article, Peter, but I have to take issue with you on this last point in your reply. My Tesla Model S is my daily driver, and having a standard RV plug available at my home provides more than adequate recharging capability. Even if I come home at night at near-zero power in the battery, by the time I wake up, the 85kWh pack is full again. I think perhaps once in the past twenty years would the 240v/40A recharge easily available to a homeowner not been sufficient to my needs.

On long road-trips, one wants more — but having that at home doesn’t help! That’s where the Level 3 infrastructure (DC fast charge) really matters.

Thanks for pointing that out Susan. It’s a critical detail that vastly helps the situation. Peter, yes it would take a lot of real estate to create an 85 kW array (assuming you wanted to fully charge directly from the sun in about an hour). About 8500 square feet. An array 50 feet by 200 feet could probably handle this. However, there is more to the equation than that. Because not everyone will want to charge at noon, they’ll need to have some sort of local battery storage for the power generated by the array. So the way you have to look at it is take the total amount of expected power to be charged during a day, divide that by the number of hours of peak sunshine on average you’ll get and that will tell you what size array you’ll need. I suspect in some parts of the country it’s going to be pretty large, but probably won’t take any more real estate than your typical gas station (albeit it won’t be able to service 10′s of vehicles simultaneously)